Collagenous spherulosis

Collagenous spherulosis is a benign lesion characterized by the presence of acellular eosinophilic and fibrillary spherules, surrounded by a proliferation of bland, round to oval myoepithelial cells. It is usually an incidental finding associated with intraductal papilloma, sclerosing adenosis, or radial scar.

The aspirates contain scattered metachromatic hyaline globules, associated with numerous benign ductal cells. The differential diagnosis includes adenoid cystic carcinoma, although the clinical findings facilitate the correct diagnosis.